<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../../js/vue.js"></script>
</head>
<body>
<div id="id_div">
    <span v-if="seen">能看到我吗</span>
</div>
<script>
    const app=new Vue({
        el:"#id_div",
        data:{
            seen:true //修改为false时，span不可见
        }
    })
</script>
</body>
</html>